Hi! I read that I could get to Lugu Lake from Chengdu, with a train from Chengdu to Xichang first.

Well, there is no direct train to the lake. First of all, you may take a train to Xichang. It takes 8.5 to 11 hours, not 7 to 8 hours. Upon arrival, take a mini bus to Xichang Bus Station for about CNY 3. Then, transfer to a bus to the lake. I remember that the bus departs at 8:30, and the trip takes about 7.5 hours. Have a nice trip!